Abstract

The operation of remote offshore pipelines, particularly those under seasonal ice cover, may need a means of detecting potential leaks at any point along the pipeline and at any time. Potential leak cases of interest are pinhole leaks out of the bottom of the pipe due to corrosion, weld or seam cracks, or damage due to third-party contact. Technologies are desired to provide leak detection coverage around the clock over long lengths of pipeline. One potential technology is distributed temperature sensing.

A key element of evaluating the applicability of leak detection systems is to characterize the behavior of leaks. It is important to understand how leaks behave when employing a technology that has only been previously used for other conditions. A joint-industry program was initiated to evaluate the thermal behavior of hypothetical underwater leaks. The environments studied range from shallow, Arctic applications to deep offshore installations. Analytical models were assessed to predict the jetting behavior of simulated leaks and their near-field thermal responses. These models were validated by means of laboratory experiments.

This information can be leveraged by a number of technologies, as the data are independent of the measurement mechanism. While the intention of this work is to evaluate distributed fiber-optic systems, the data on leak characteristics may also provide indications of applicability of other techniques for detecting potential underwater leaks. The data from this project will allow the industry to improve the understanding of potential leaks from underwater pipelines and, hence, lay the foundation for determining appropriate detection systems.

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